Superparamagnetic iron oxide nanoparticles are widely used as nanoprobes for magnetic resonance imaging (MRI).
Water-soluble iron oxide nanoparticles were synthesized by coating iron oxide nanoparticles with a hydrophilic,
biocompatible, biodegradable poly(amino acid) derivative, poly(2-hydroxyethyl aspartamide) graft copolymer for
negative contrast enhancement on T2 weighted MRI. HER2/neu antibodies were conjugated on the surface of
poly(amino acid) coated iron oxide nanoparticles for the detection of breast cancer. The antibody-grafted iron
oxide nanoparticles (PAION-Ab) were about 31.1 nm in diameter. The T2 relaxivity of PAION-Ab was 246
L·mmol-1 · sec-1 greater than that of the commercial product such as Feridex. PAION-Ab showed low cytotoxicity
even at relatively high concentrations. Furthermore, Prussian blue staining and in vitro MRI study with SKBR-3,
breast cancer cells overexpressing HER2/neu receptors indicated that PAION-Ab exhibited excellent cancer cell
detection ability and enhanced signal intensities in the T2-weighted image.